Implement entering gating moves with mouse

[xboard.git] / backend.c

diff --git a/backend.c b/backend.c
index 05f7dfc..958c92e 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -6340,6 +6340,8 @@ Explode(Board board, int fromX, int fromY, int toX, int toY)
     return FALSE;
 }
 
+ChessSquare gatingPiece = EmptySquare; // exported to front-end, for dragging
+
 void LeftClick(ClickType clickType, int xPix, int yPix)
 {
     int x, y;
@@ -6396,6 +6398,7 @@ void LeftClick(ClickType clickType, int xPix, int yPix)
     autoQueen = appData.alwaysPromoteToQueen;
 
     if (fromX == -1) {
+      gatingPiece = EmptySquare;
       if(!appData.oneClick || !OnlyMove(&x, &y, FALSE)) {
        if (clickType == Press) {
            /* First square */
@@ -6429,7 +6432,7 @@ void LeftClick(ClickType clickType, int xPix, int yPix)
        /* Check if clicking again on the same color piece */
        fromP = boards[currentMove][fromY][fromX];
        toP = boards[currentMove][y][x];
-       frc = gameInfo.variant == VariantFischeRandom || gameInfo.variant == VariantCapaRandom;
+       frc = gameInfo.variant == VariantFischeRandom || gameInfo.variant == VariantCapaRandom || gameInfo.variant == VariantSChess;
        if ((WhitePawn <= fromP && fromP <= WhiteKing &&
             WhitePawn <= toP && toP <= WhiteKing &&
             !(fromP == WhiteKing && toP == WhiteRook && frc) &&
@@ -6447,6 +6450,11 @@ void LeftClick(ClickType clickType, int xPix, int yPix)
                ClearHighlights();
            }
            if (OKToStartUserMove(x, y)) {
+               if(gameInfo.variant == VariantSChess && // S-Chess: back-rank piece selected after holdings means gating
+                 (fromX == BOARD_LEFT-2 || fromX == BOARD_RGHT+1) &&
+               y == (toP < BlackPawn ? 0 : BOARD_HEIGHT-1))
+                 gatingPiece = boards[currentMove][fromY][fromX];
+               else gatingPiece = EmptySquare;
                fromX = x;
                fromY = y; dragging = 1;
                MarkTargetSquares(0);
@@ -6470,6 +6478,7 @@ void LeftClick(ClickType clickType, int xPix, int yPix)
            /* Second up/down in same square; just abort move */
            second = 0;
            fromX = fromY = -1;
+           gatingPiece = EmptySquare;
            ClearHighlights();
            gotPremove = 0;
            ClearPremoveHighlights();
@@ -6534,6 +6543,8 @@ void LeftClick(ClickType clickType, int xPix, int yPix)
     // off-board moves should not be highlighted
     if(x < 0 || y < 0) ClearHighlights();
 
+    if(gatingPiece != EmptySquare) promoChoice = ToLower(PieceToChar(gatingPiece));
+
     if (HasPromotionChoice(fromX, fromY, toX, toY, &promoChoice)) {
        SetHighlights(fromX, fromY, toX, toY);
        if(gameInfo.variant == VariantSuper || gameInfo.variant == VariantGreat) {